A known method is to advance a finite length of featureless material into a cutting zone, and while the material is stationary, moving a laser beam about on a X-Y positioner for cutting a pattern from the material. A numerically-controlled positioner positions the laser beam over the material in response to a predetermined known pattern. Once the pattern is cut the conveyor advances to eject the cut pattern and bring new material into the cutting zone.
In Canadian Patent Application published as 2,016,554 in Nov. 11, 1991, a method is disclosed which partially achieves the objective of increasing the throughput of cut patterns by enabling laser cutting while material is moving on a conveyor in a continuous manner through a laser cutting zone. This “Cut-on-the-Fly” method eliminates the loading and unloading of material from the cutting zone and it employs efficient movement of the laser cutting head both along the axis of the moving material as well as across the material. In U.S. Pat. No. 6,294,755 B1, issued Sep. 25, 2001 to Lacent Technologies Inc., of Edmonton, Alberta, CANADA, it is disclosed to further optimize and increase the throughput of cut material by minimizing the time required to move the laser along a continuous path by discretizing the path into geometric moves, pairs of which are joined to minimize positioner stop and go. Further, ranges of velocities are analyzed for each discrete move and are adjusted to overlap for fitting a continuous velocity curve therethrough.
The above techniques have been based upon a substantially uniform material and the pattern exists only in the cutter's numeric storage. In other words, the pattern can be implemented anywhere on the continuously moving material. However, in certain instances it is desirable to locate and cut out a shape which is already printed or otherwise preset in the material. There are a number of challenges involved in cutting out shapes or patterns whose coordinates in the materials are invariant including: locating where to start cutting and cutting along the shape's predetermined cut lines or within a certain tolerance thereof. The above challenges are worsened in the situations where the material is moving continuously, where the material may skew from the start of cutting to the end of cutting.
It is known in the clothing and furniture industry to cut patterned materials for later assembly. In such instances, a finite number of starting positions are known. An example of such technology is as set forth in U.S. Pat. No. 5,975,743 to Bercaits and U.S. Pat. No. 4,905,159 to Loriot. It is known in the art to use a vision system which may be utilized to locate a starting point, however, to date the camera of such vision systems are carried by the cutter and therefore can only be applied serially; to seek within a carefully defined area for locating the start point, and then resetting to begin the cutting process. Another approach to cutting out the shape is to pre-mark boundaries or cut lines of the shape with identifying markers, then to trace the marker with a cutter. To applicant's knowledge, the cutting of preset shapes from a moving sheet of material has not been achieved in a satisfactory manner.
Applicant has not found the abovementioned technologies provide increased accuracy, higher throughput and operation with more sophisticated materials.